Discovery of a ‘‘conductor'' in muscle development

A team led by Jean-François Côté, researcher at the IRCM and professor in the Department of Medicine at the Université de Montréal, identified a ‘‘conductor'' in the development of muscle tissue. The discovery, published online yesterday by the scientific journal Proceedings of the National Academy of Sciences (PNAS), could have an important impact on the treatment of muscular diseases such as myopathies and muscular dystrophies.

“For several years, we have been studying myogenesis, a process by which muscles are formed during embryonic development,” says Jean-François Côté, PhD, Director of the Cytoskeletal Organization and Cell Migration research unit at the IRCM. “During the last step of this process, muscle cells called myoblasts align and fuse together to form muscle fibers.”

The fusion of myoblasts is a critical step in the formation of embryonic muscle fibers as it determines muscle size, among other things. This process is also important in adult life because muscle stem cells fuse with existing fibers to achieve muscle growth and help regenerate damaged muscles. However, until now, fusion remained a poorly understood step within the scientific community.

“We were able to identify the receptor BAI3, a protein at the surface of myoblasts, as one of the crucial missing links in the fusion of muscle cells,” adds Dr. Côté. “In fact, this receptor acts much like an orchestra conductor by activating a signalling pathway required for this important process.”

In 2008, Dr. Côté's team explained the role of the DOCK1 and DOCK5 genes in the development of muscle tissue by showing that these two genes were critical regulators of the fusion process in mice. In their most recent study, the researchers confirmed receptor BAI3's essential role by blocking its interaction with the DOCK signalling pathway. They discovered that, as a result, myoblast fusion was also blocked.

“Our scientific breakthrough will undoubtedly have a translational research application on the regeneration of tissue from stem cells, given that a better understanding of the molecular mechanisms of fusion are required for the development of such therapies,” concludes Dr. Côté. “This could therefore have an impact on the treatment of muscular diseases, including myopathies and muscular dystrophies.”

About the study

Dr. Côté's research was funded by the Canadian Institutes of Health Research. The IRCM researchers involved in this project were Noumeira Hamoud, first author of the article, Viviane Tran, Louis-Philippe Croteau and Artur Kania, Director of the Neural Circuit Development research unit.

For more information, please refer to the article summary published online by PNAS.

About Jean-François Côté

Jean-François Côté obtained a PhD in biochemistry from McGill University. He is Associate IRCM Research Professor and Director of the Cytoskeletal Organization and Cell Migration research unit. Dr. Côté is also associate research professor in the Department of Medicine (accreditation in molecular biology and biochemistry) at the Université de Montréal, and adjunct professor in the Department of Anatomy and Cell Biology at McGill University. He is a Research Scholar from the Fonds de recherche du Québec – Santé. For more information, visit www.ircm.qc.ca/cote.

About the IRCM

Founded in 1967, the Institut de recherches cliniques de Montréal (www.ircm.qc.ca) is currently comprised of 35 research units in various fields, namely immunity and viral infections, cardiovascular and metabolic diseases, cancer, neurobiology and development, systems biology and medicinal chemistry. It also houses four specialized research clinics (cholesterol, cystic fibrosis, diabetes and obesity, hypertension), eight core facilities and three research platforms with state-of-the-art equipment. The IRCM employs 425 people and is an independent institution affiliated with the Université de Montréal. The IRCM Clinic is associated to the Centre hospitalier de l'Université de Montréal (CHUM). The IRCM also maintains a long-standing association with McGill University. The IRCM is funded by the Quebec ministry of Higher Education, Research, Science and Technology.

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For more information and to schedule an interview with Dr. Côté, please contact: